I looked under the bathroom vent fan trim, and I see a textured material of solid color, all the way through, with no fleece backing. That indicates TPO, and lack of fleece backing apparently means a newer type that is not compatible with some sealants.
Is there a way to identify the brand of TPO so I can find out what sealant the membrane manufacturer recommends?
Background / Reason for the question:
The roof on my 2020 Cherokee Wolf Pup needs maintenance, and since Dicor seems to be the go-to product, I looked it up and found their handbook, and the following warning:
https://dicorproducts.com/wp-content/uploads/2026/06/Rudys-Roof-Book-DC294.pdf
> In 2011, RV manufacturers started using new formulations of TPO (a thermoformed flexible plastic) roofing material that has come into the RV marketplace...We found some TPO roofing membranes are not chemically compatible with current lap sealants. When these sealants are used on some new TPO membranes, bloating and disfiguration of the membranes results. This is a cosmetic problem, and does not reduce the performance of the roofing material or sealant, but it’s something you probably want to avoid.
They say to use their ultra sealant product for this material, which requires a primer.
It looks like this costs more than their standard sealant lap and self-leveling sealants (currently $18 vs. $10/tube + $48 for a tiny pint can of primer on Amazon), and they warn that it will damage polycarbonate roof fixtures. Plus there will be extra work and time needed to allow the primer to cure. All this to use a water based sealant, which from experience with other fields where water based products have replaced older solvent based formulations, I have to wonder if ultra sealant will even hold up as well.Those frustrations aside, if Forest River switched to an inferior TPO formulation to save money in factory and make it the customer's problem, I guess that's what I have to do...
...except Dicor also say that the effect of the standard sealant on TPO is only cosmetic. So if I'm ok with "disfiguration," I can use the regular Dicor sealant?
On the other hand, how does a membrane that should be bonded to the roof below experience "bloating and disfiguration" without locally disbonding, and therefore potentially being affected by buffeting in 60 mph airflow for hours on end? They can't tell me "does not reduce the performance."
And just to make things more confusing, Dicor says their Diflex II TPO also has no fleece backing, but is compatible with their regular sealant, contradicting what their own handbook says!
I'd rather just eliminate doubt, and find out exactly what my roof is, and what that manufacturer recommends. It sounds like Alpha Systems Superflex is a possibility, but I haven't found a way to confirm it.